The present invention is in the field of plant growing systems and is specifically directed to the field of seedling growing, particularly greenhouse growing such as the growing of tomato seedlings and the like.
Earlier U.S. Pat. No. 3,667,159 discloses a seedling flat formed of foamed plastic as shown in FIGS. 1 and 2 of said patent in which planting cells 32 are provided with lower openings 34 and are tapered downwardly so that the seedlings can be easily removed. Seedlings have been grown in such flats with watering being effected by overhead spray means, a procedure that is wasteful of water and inducive of disease in the plants. The present invention is directed to a unique system for handling flats of the aforementioned type and for providing nutrients to seedlings in such flats by the floatation of the flats on nutrient containing liquid so that the nutrient containing liquid flows upwardly into the planting cells through the lower openings 34.
It has been previously proposed to provide seedling plants in a support from which the plant roots downwardly extend into a floodable trough or the like which is periodically flooded to provide water and/or nutrients to the roots. Examples of such devices are found in U.S. Pat. Nos. 3,451,162; 3,925,926; 4,324,069 and 4,327,538. U.S. Pat. No. 4,486,977 also discloses similar concepts.
It has additionally been proposed to provide floating plant flats or the like which float on a body of liquid providing nutrients for plants in the flat as shown in U.S. Pat. Nos. 2,175,113; 2,531,562; 3,927,491; 4,028,847; 4,034,506; 4,037,360; 4,312,152; 4,468,885; and 4,513,533. Additionally, British patent Nos. 1,031,309; 1,038,320; 1,053,508; and 1,313,121 also disclose similar floating plant flat systems.
It has also been proposed to provide a trough including wire means for supporting a plant container such as in U.S. Pat. No. 4,075,785. Similarly, Austrian patent No. 241,896 appears to disclose the use of wire supports for plant flats. Other prior art devices of interest include U.S. Pat. Nos. 4,004.369 and 4,166,341.